For the second straight season as the No. 1 overall seed in the NCAA men's hockey tournament, St. Cloud State has lost in its opening game.
American International College scored in each of the first two periods and held on to win 2-1.
Last year, St. Cloud State was also the 16-team tournament's top seed but was eliminated after dropping its opener 4-1 to Air Force.
This is the third time in the past five seasons that the No. 1 overall seed has lost in the first round, as top seed Minnesota State was eliminated early in 2015.
Four years ago, American International had the third-worst winning percentage in Division I after going 4-25-7.
American International was a 20-to-1 underdog against St. Cloud State on Friday and is 300-to-1 to win the tournament. Arizona State and Harvard have the next longest odds to be national champion, both at 40-to-1.